By Brandon Johnson and Mike McEvoy
On August 16, 2007, at 10:30 a.m., the Hebron (KY) Fire Protection District was dispatched to an unknown gas problem in a private residence. The dispatch center advised it had lost contact with the caller but still had an open line. Initial response included an engine, an ambulance, a chief, and a sheriff’s patrol.
Arriving units found an ashen, 15-year-old male sitting in the driveway. He was alert but disoriented and complained of a headache. He had been inside the residence and was awakened by his ringing cell phone and then noticed the smell of “propane or something.” He proceeded to phone a nearby relative and then unsuccessfully tried to awaken three other people inside the residence. After calling 911, he left the house to await the fire department’s arrival.
Fire crews on-scene donned breathing apparatus and made entry into the residence to locate the three others and an additional relative, who had arrived prior to the fire department and apparently had entered the residence. Firefighters located and removed four individuals including two 17-year-olds, a 19- and a 45-year-old, as well as two cats and a dog from the home. All had been sleeping; two of the animals were unconscious. Apparently, the 19-year-old had been listening to the vehicle radio in the garage when he became tired and went to bed, forgetting to turn off the running vehicle. He was unsure of what time this occurred.
 (1) The CO poisoning scene. A vehicle was found running inside the garage. [Photos courtesy of the Hebron (KY) Fire Protection District.] |
Returning to the residence with a four-gas monitor, firefighters encountered 800 ppm of carbon monoxide (CO) at the front door. A search of the home found a running vehicle in the garage with the garage door closed. The highest CO reading obtained was 936 ppm with volatile organic compounds (VOCs) at 2.6, lower explosive limit (LEL) six percent, and oxygen 19.1 percent. Fresh animal feces and vomit from the cats and dog were scattered throughout the home. The vehicle engine was barely operating, probably because of the oxygen-deficient atmospheric conditions. There were no working CO detectors inside the residence.
 (2) Firefighters used a four-gas monitor to evaluate atmospheric conditions inside the residence. |
EMS examined the five patients who had been in the residence. All had difficulty walking and complained of severe headaches. Using a pulse CO-oximeter, EMS measured each patient’s blood carbon monoxide levels. CO in the body binds to red blood cells (hemoglobin), forming carboxyhemoglobin, referred to as SpCO when measured with an oximeter. SpCO was measured at 40 percent for the two 17-year-olds and 45 percent for the 19-year-old. The 15-year-old who met the fire department outside had an SpCO of 35 percent, and the relative who arrived and entered the home some 10 minutes prior to the firefighters measured 20 percent SpCO. All victims were placed on 100 percent oxygen by nonrebreather mask, effectively lowering SpCO levels during treatment and transport.
The fire department contacted animal control to care for the animals while the occupants of the home were transported to local hospitals. The four individuals who had been in the residence for the longest time were transported to a hyperbaric oxygen (HBO) therapy-capable facility at the regional university teaching medical center hospital. The 19-year-old, who had the highest SpCO and the most significant symptoms, was treated with HBO. Despite this, he suffered long-term neurological deficits. Interestingly, staff at the receiving hospital were unfamiliar with noninvasive CO-oximetry and somewhat skeptical of the firefighter paramedic assessments of CO toxicity in the patients.
LESSONS LEARNED
This incident illustrates several important lessons.
How many unfounded CO alarms have you responded to? Keep this in mind: A structure can be ventilated in seconds; CO remains bound to hemoglobin in the blood of an exposed patient for days. Why not take advantage of the ability to measure CO in occupants to make certain that we’re not falsely reassuring homeowners they can safely return to their residence?
A CO-oximeter can be incredibly useful when confronted with a symptomatic CO-poisoned patient. Quantifying a COHb level helps EMS providers select an appropriate transport destination, especially given our present knowledge of the benefits of HBO for certain subsets of CO-poisoned individuals.5 In multiple patient situations such as this incident, a CO-oximeter allows rapid screening of large numbers of potentially exposed individuals. When confronted with tens or hundreds of potentially CO exposed patients, the ability to screen on-scene can avoid overwhelming local hospital emergency department resources.
The fire service can play a key role in prevention and response to CO incidents. This incident illustrates the use of technology and safety equipment to protect the responders and best assess, evaluate, and transport the affected civilians. Using all the tools available to the fire service can dramatically reduce the misdiagnosis of CO poisoning and provide comprehensive assessment of not only property but also the valuable lives of the occupants inside.
References
1. Flynn, J, “CO Deaths,” NFPA Journal; 2008:102(1) January/February, 32-5.
2. Grace TW, FW Platt, “Subacute carbon monoxide poisoning: Another great imitator,” JAMA; 1981:246(15), 1698-700.
3. Heckerling PS, JB Leiken, A Maturen, “Occult carbon monoxide poisoning: validation of a prediction model,” American Journal of Medicine; 1988:84(2),251-6.
4. Centers for Disease Control and Prevention, “Carbon Monoxide Poisoning Prevention Clinical Education,” September 20, 2007, clinician training Web cast. Archived at www2a.cdc.gov/phtn/COPoisonPrev/default.asp.
5. Weaver LK, RO Hopkins, KJ Chan, S Churchill, CG Elliott, TP Clemmer, JF Orme Jr, FO Thomas, AH Morris, “Hyperbaric oxygen for acute carbon monoxide poisoning,” New England Journal of Medicine; 2002:347(14),1057-067.
6. NFPA 720, Standard for the Installation of Carbon Monoxide (CO) Warning Equipment in Dwelling Units (2005 edition). National Fire Protection Association. www.nfpa.org.
7. Abelsohn, A, MD Sanborn, BJ Jessiman, E. Weir, “Identifying and managing adverse environmental health effects: 6. Carbon monoxide poisoning,” Canadian Medical Association Journal; 2002:166 (13), 1685-90.
8. Kao LW, KA Nanagas, “Carbon monoxide poisoning,” Emergency Medicine Clinics of North America; 2004:22(4), 985-1018.
9. Henry CR,D Satran, B Lindgren, C Adkinson, C Nicholson, TD Henry, “Myocardial Injury and Long-Term Mortality Following Moderate to Severe Carbon Monoxide Poisoning,” JAMA; 2006:295(4), 398-402.
Brandon Johnson is the assistant director and toxmedic coordinator for the Northern Kentucky Regional WMD Hazmat Response Unit, a firefighter/paramedic with the Hebron (KY) Fire Protection District, and a paramedic instructor with the University of Cincinnati Paramedic Education Program.
Mike McEvoy is the EMS technical editor for Fire Engineering, a critical care nurse, an instructor in critical care medicine, and a co-chair of the Resuscitation Committee at Albany (NY) Medical Center. He is also the EMS coordinator for Saratoga County, New York, and chief medical officer for the West Crescent (NY) Fire Department.
